U of A researcher refutes claims about underground fungal networks in forest trees

“We don’t want to be relying on misinformation to be making policy or management decisions on forests," U of A researcher says.

The term “wood-wide-web” is used to describe forest trees that are able to communicate with each other through a vast array of interconnected fungal networks underground. However, researchers are questioning whether the “wood-wide-web” is beneficial to forest trees and their seedlings. 

Justine Karst, an associate professor in the department of renewable resources at the University of Alberta, doesn’t think that they are as beneficial to trees as other research has shown.

Karst, along with Melanie Jones, a biology professor at the University of British Columbia, and Jason Hoeksema, a biology professor at the University of Mississippi, recently published a paper analyzing the true nature of mycorrhizal fungal networks, and how they are potentially beneficial to trees and forests. 

Common mycorrhizal networks (CMN) are fungal networks that settle into the tree’s root tip and gather resources, such as water and nutrients. They then transfer these resources to their plant host which photosynthesizes and makes sugars that float back to the mycorrhizal fungi.

“It’s mutualism, which is what we usually call it,” said Karst.

Karst and her colleagues analyzed three popular claims in their paper, the first being that CMNs are widespread in forests. They chose this claim because they “don’t really know how widespread they are, and this hasn’t actually been looked at in many forest types.” 

Through their research, Karst and colleagues found mycorrhizal networks in only two forest types that had been mapped. In light of this information, the claim that mycorrhizal networks are widespread in forests was disputed by Karst and colleagues, because the “support is quite limited,” simply due to the fact that not enough forests have been mapped to definitively make this claim.

The second claim analyzed in the paper is that “seedlings are able to benefit from being plugged into that mycorrhizal network through resource transfer.” Although they searched for field studies to corroborate this claim, they found little evidence that resource transfer is present through this fungal network.

“We also found that there’s a lot of potential alternative explanations to experiments that are often overlooked or not discussed,” Karst said.

In most experiments that they looked at, the seedlings showed “no response to potential access to mycorrhizal networks.” 

The third claim they analyzed is that trees are able to send defense signals or alarm calls to their offspring through mycorrhizal networks. Although this would be a beneficial biological safety mechanism, Karst said that she has doubts.

“We couldn’t find a single peer-reviewed, published study in the field testing these ideas so it remains to be demonstrated if this is true.”

Karst believes this research to be extremely important because they found that almost 50 per cent of papers that cite older studies are making an inaccurate statement.

“We don’t want to be relying on misinformation to be making policy or management decisions on forests, so there’s that level of why there’s a concern.”

She added that this research is useful for the management, policy creation, conservation, restoration, and protection of forests. To do these things correctly, Karst believes that “we want to have the most solid science available to us.” 

The other reason that it is important to crack down on the accuracy of this research is because if this misinformation is not brought to light, “the credibility of the science enterprise is eroded,” Karst said. It’s extremely beneficial for researchers in this field to “consolidate their knowledge,” so they can expand their research even further. 

As of right now, Karst is just trying to “reach out to the research community” and spread the word about their findings. They are also working on translating their paper into a more accessible language to allow greater access for the general public.

“I’ve had various societies invite me to give talks about our research. So at this point, we’re really just trying to get our message out there: here’s what we found, here’s why it’s important, and here’s why we need to rethink some of these ideas because, as you probably know, they are widespread.” 

Karst’s immediate plans involve focusing on reorienting the field of mycorrhizal research, and possibly giving talks and lectures to inform people about the impacts and importance of this research.

Peris Jones

Peris Jones is the 2024-25 News Editor at The Gateway. She previously served as the 2023-24 Deputy News Editor. She is in her third year, studying media studies and English. In her free time, she loves going to the gym, shopping, and watching movies with her friends.

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